Core B: The HAALSI program comprises four subprojects that focus on 1) physical and cognitive functioning; 2)cardiometabolic risks; 3) aging with HIV; and 4) economic well-being and productivity. The program links new longitudinal surveys among respondents ages 50 years and older in three INDEPTH sites (Agincourt, Ifakara and Navrongo) with the long-running health and demographic surveillance systems (HDSS) already in place in those sites. A central requirement in all four subprojects is valid information on mortality by age and cause. The Mortality Core (Core B) will leverage existing infrastructure within the HDSS sites to monitor mortality and migration and use this to inform the longitudinal surveys conducted through this program. The Mortality Core will assist all subprojects by providing accurate, consistent, comparable measures of all-cause and cause-specific mortality and assure that migration is appropriately addressed to provide a full accounting ofthe study cohorts. The Core will develop standardized data definitions and data extraction procedures that can be used by all participating sites to produce the required indicators from their routine longitudinal health and demographic surveillance. In addition, monitoring ofthe study cohorts will require new methods and procedures to account for the study populations at each site and minimize loss to follow-up of the program cohorts. The Mortality Core has three specific aims: 1. Measure all-cause mortality consistently across HDSS study centers. 2. Develop/adapt methods to produce comparable, valid cause of death assessments from verbal autopsies. 3. Develop methods to minimize loss to follow-up for those who migrate from the study site over the long or short term.